The Food and Drug Administration has approved a breast implant manufactured by Allergan (NYSE: AGN). The California-based company's Natrelle 410, a silicone-gel filled implant, may now be used for breast reconstruction, augmentation, and revision surgery in women who are at least 22 years of age.

The FDA's approval is conditional. The requirements include mandates for the company to monitor the product's effects on 3,500 patients for a period of five years, analyze the Natrelles that are removed from patients and returned to the firm, and evaluate patient perceptions of the product's labeling.

The FDA said that, with this decision, there are now four silicone gel breast implant products approved in the U.S.